ML20215N788
| ML20215N788 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 10/24/1986 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 2326K, NUDOCS 8611070273 | |
| Download: ML20215N788 (3) | |
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N Commonwealth Edison i
One First National Plaza, Chicago, Illinoiq
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/ Address Reply b: Post Offico Box 767 i/ Chicago, Illinois 60690 - 0767 October 24, 1986 i
Mr. Harold R.
Denton, Director Office of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission-Washington, DC. 20555
Subject:
Byron Unit 2 Interim operation of HVAC Systems NRC Docket No. 50-455
References:
(a)
October 1, 1986 letter from D.L. Farrar to H.R.
Denton (b)
August 11, 1984 letter from T.R. Tramm to H.R.
Denton i
Dear Mr. Denton:
The purpose of this letter is to provide the technical justification to allow for interim operation of the Byron Unit 2 HVAC Systems.
As with Byron Unit 1, temporary leak limits are being imposed pending completion of testing on the_ Unit 2 Auxiliary Building Ventilation System.
Prior to July 1, 1987, the leak rate from the Energency Core Cooling System (ECCS) in the Auxiliary Building will be determined in the same manner as'descritmd in reference (b) for Byron Unit 1.
Until testing of the Uttit 2 Auxiliary Building ventilation system is complete, Byron Unit 2 Will not be operated at power levels exceeding 30%, unless.the Auxiliary Building ECCS leakage can be shown to be below the corresponding limit presented in Figure 1 (attached).
As presented in reference (a), if the ECCS l
leakage is reduced, Byron Unit 2 can safely operate at higher I
reactor power levels without HEPA and charcoal filtration and without negative pressures.
Figure 1 indicates the allowable Unit 2 power level at any given Unit 2 ECCS leakage rate without filtration of Unit 2 area exhaust air and with acceptable low population zone (EPZ), exclusion area boundary (EOB) and control room doses.,The offsite and control room dose analysis assumes continuous ECCS leakage of 1 gallon per minute.
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' As shown in Figure 1, Byron Unit 2 can, potentially, operate at a reactor power level of 100% with the auxiliary building ventilation system inoperable,.without exceeding offsite and control room dose limitations.
Once the Byron Unit 2 Auxiliary Building ventilation equipment is declared operable, these limits will no longer apply.
Because of the short duration of this limitation, no on-going surveillance will be conducted once the leak rate has been found to be acceptable for a given power level.
Should you have any questions on this matter, please contact this office.
One signed original and fifteen (15) copies of this letter and the attachment are provided for your review.
Very truly yours,
~tefW S.C. Hunsader Nuclear Licensing Administrator
/klj.
cc:
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'50 RUXILIRRY BUILDING ECCS LERK RATE fGAL'/HR) 1 1
FIGURE 1.
MAXIMUM POWER LEVEL VS. ECCS EQUIPMENT LERKAGE 1
j Assumptions:
- 25 CFM Control Room Unfiltered 'Inleakage 4~
- Thyroid Dose Calculations Include Contributions From:
- 1. Containment Leakage;
- 2. Massive ECCS Leakage (50gpm for 30 min. at T=24 hours);
- 3. Thirty (30) day ECCS Continuous Leak' age as shown on curve.
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